uint8_t pattern = 0b01010101;
#define dataPin 2
#define latchPin 3
#define clockPin 4
int i=0;
bool smer = true;

void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  Serial.begin(9600);
  
}

void loop() {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, LSBFIRST ,pattern);
  digitalWrite(latchPin, HIGH);
  i=(i+1)%1;
  pattern = (smer)?pattern<<1:pattern>>1;
  if(i==0){
    smer = !smer;
  }
  delay(250);
 
}